I am trying to replicate the Interesting Moments section through the API.

I am able to get an access_token via client_id and client_secret. I am able to get a Marketo ID via SFDCLeadId. I am able to get a pagingtoken via sinceDatetime. (used July 1 2017) Looking at Salesforce I am able to see this Lead has interesting moments since July 1 2017.

Why isnt the Interesting moment that I see in Salesforce displayed here?

Why is the moreResult attribute true? Even though no results are returned... If I use the new nextPageToken in another callout as you would in a more than 300 results situation, I basically get the same response, no real results but a new nextPageToken is given and moreResult is still true.

Think of it like this. You've asked your intern to grab a copy of Harry Potter and the Sorcerer's Stone and notate every page and sentence number that mentions Professor Snape. You've also told him every 15 minutes he needs to check in with you and report what he's found so far and where he stopped in the book (you've had bad luck with interns goofing off in the past). The first few check-ins he brings you a blank piece of paper and where in the book he stopped; Snape isn't introduced immediately so there's no mention for him to document but the intern continues to read. Eventually you'll start getting a couple references, then many references, with the volume ebbing and flowing depending on how much the story focuses on Snape at any point in time.

That's basically how that endpoint works. It pages through all the activities in the database looking for what activities qualify for what you specified. Sometimes it finds none in the amount of time the call is allowed to stay open but it comes back, returns a pointer of where it stopped, and says it's not done searching yet.

The alternative is having your intern run a digital copy of Harry Potter through a script that spits out all the page and sentence numbers in one go. That's kind of like how the Bulk Activity Export endpoint works.